1. Field of the invention
The present invention concerns gas-fired direct heat steam ovens, in particular ovens for cooking food products.
2. Description of the Prior Art
Combined steam and gas ovens are described in documents EP-A-0 277 888 (U.S. Pat. No. 4,823,766) and EP-A-0 409 685 (U.S. Pat. No. 5,016,605), for example.
A gas-fired direct heating and convection oven of this known kind essentially comprises an enclosure enclosed by a peripheral wall and a door, the interior space of the enclosure comprising a first part receiving food products to be cooked and a second part containing at least one gas burner connected to a system supplying a mixture of gas and pressurized combustion-supporting air and at least one fan for circulating hot air through both parts of the enclosure.
Various solutions have been proposed for the problem of preventing water forming and stagnating in the gas burner due to condensation of the steam. In document EP-A-0 277 888 the gas burner is on the downstream side of the fan in the flow of air caused by the fan and is in the lower part of the enclosure, the flame outlet orifices being directed upwards. Auxiliary heating means maintain the burner at all times at a temperature higher than the temperature at which water vapor condenses, so preventing the formation of liquid water in or on the burner. A solution of this kind is not satisfactory, however, and in particular causes significant disturbance of the flame.
In document EP-A-0 409 685 the gas burner is on the upstream side of the fan in the flow of air caused by the fan and in an intermediate part of the enclosure between a first partition wall separating it from the part containing the food to be cooked and a second partition wall separating it from the part occupied by the fan. The burner is in an upper part of the enclosure and oriented to direct the flame downwards, favoring the draining off of any water formed by condensation in the burner. This solution substantially increases the overall size of the functional units of the oven, so reducing the volume of the part for receiving the foods to be cooked. Furthermore, cleaning the various functional units entails demounting two successive walls and this is particularly difficult because of the presence of various sensors associated with the burner for monitoring or controlling the gas flame.
The problem to which the present invention is addressed is that of designing a new gas-fired direct heating steam oven in which all the functional units such as the fan and the burner are included in a single enclosure part in order to occupy a small space, a single wall separating this enclosure part from the part to receive the foods to be cooked, and in which means are provided to prevent the accumulation of condensed water in the burner and to favor the stabilization and the continuity of the gas flame.
Another object of the invention is to facilitate significantly the cleaning of the functional units of the oven and to reduce the risk of damage to these functional units during cleaning.
The invention also enables better distribution of the flame in the burners, improving combustion and the distribution of heat.